Device and Method for Increasing the Heat Yield of a Heat Source

ABSTRACT

Various embodiments include a device for increasing the heat yield of a heat source comprising: a heat sink; a heat pump with a condenser and an evaporator; and a heat sink feed and a heat sink return providing a thermal coupling to the heat source with a heat exchanger. The condenser is thermally coupled to the heat sink feed for emitting heat to the heat sink. The evaporator is thermally coupled to the heat sink return for absorbing heat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application of InternationalApplication No. PCT/EP2018/061001 filed Apr. 30, 2018, which designatesthe United States of America, and claims priority to DE Application No.10 2017 208 079.5 filed May 12, 2017, the contents of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to thermal management systems. Variousembodiments may include devices and/or methods for increasing the heatyield of a heat source in a thermal management system.

BACKGROUND

Waste heat from industrial processes or heat from geothermal sources isoften used to provide heat for a heat consumer, i.e. emit this to a heatsink. The heat is typically transmitted to the heat sink by means of aheat transmitter or an additional heat pump. If the heat provided by aheat source is transmitted to the heat sink by means of a heatexchanger, the heat sink typically has a heat sink return and a heatsink feed for a fluid in connection with said heat exchanger. Here, theheat sink return has a lower temperature than the heat sink feed. Inother words, at least some of the heat is consumed by the heat sink.

Similarly, the heat source typically has a heat source return and a heatsource feed in connection with the heat exchanger. Here, the temperatureof the heat source feed is greater than the temperature of the heatsource return because of the transmission of heat by means of the heatexchanger. Because of the thermal coupling of the heat source to theheat sink by means of the heat exchanger, the temperature of the heatsource return is restricted by the temperature of the heat sink return.In other words, the temperature of the heat source return cannot belowered further if heat is to be transmitted to the heat sink.

Furthermore, the temperature of the heat sink feed is restricted by thetemperature of the heat source feed. Said restrictions lead to thedisadvantage that the heat content of the heat source cannot be fullyutilized. In other words, the heat yield of the heat source is therebyrestricted.

SUMMARY

The present disclosure provides teachings useful for improving the heatyield of a heat source. For example, some embodiments include a device(1) for increasing the heat yield of a heat source (6), comprising: aheat sink (2) and a heat pump (4) with a condenser (41) and anevaporator (42); wherein the heat sink (2) has a heat sink feed (21) anda heat sink return (22) in connection with a thermal coupling to theheat source (6) by means of a heat exchanger (12); and the condenser(41) of the heat pump (4) is thermally coupled to the heat sink feed(21) for emitting heat to the heat sink (2); characterized in that theevaporator (42) of the heat pump (4) is thermally coupled to the heatsink return (22) for absorbing heat.

In some embodiments, the device comprises the heat source (6), whereinafter the evaporator (42) of the heat pump (4), the heat sink return(22) is thermally coupled to the heat source (6) by means of the heatexchanger (12) for absorbing heat.

In some embodiments, the condenser (41) of the heat pump (4) isthermally coupled to the heat sink return (22) by means of a bypass line(23).

In some embodiments, the heat sink (2) is part of a district heatingnetwork.

In some embodiments, the heat source (6) is a geothermal source and/oran industrial waste heat source.

In some embodiments, the heat pump (4) is configured as ahigh-temperature heat pump.

In some embodiments, the heat pump (4) comprises a working fluid withR1233zd, R1336mzz, butane, cyclopentane and/or with a fluoroketoneand/or a mixture of said substances.

In some embodiments, the heat pump (4) has an electrical power of atleast one Megawatt.

As another example, some embodiments include a method for increasing theheat yield of a heat source (6) with a device as claimed in any of thepreceding claims, comprising the steps: heat transmission from the heatsource (6) to the heat sink return (22) by means of the heat exchanger(12); heat transmission from the condenser (41) of the heat pump (4) tothe heat sink feed (21); and characterized by a heat transmission fromthe heat sink return (22) to the evaporator (42) of the heat pump.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features, and details of the teachings herein areillustrated in light of the exemplary embodiments described below andfrom the drawings. These show diagrammatically:

FIG. 1 a yield of the heat source by means of a heat pump according tothe prior art;

FIG. 2 a device incorporating teachings of the present disclosure; and

FIG. 3 a device incorporating teachings of the present disclosure.

Similar or equivalent elements, or those with the same function, maycarry the same reference signs in the figures.

DETAILED DESCRIPTION

In some embodiments, a device for increasing the heat yield of a heatsource comprises at least:

-   -   a heat sink and a heat pump with a condenser and an evaporator;        wherein    -   the heat sink has a heat sink feed and a heat sink return in        connection with a thermal coupling to the heat source by means        of a heat exchanger; and    -   the condenser of the heat pump is thermally coupled to the heat        sink feed for emitting heat to the heat sink and the evaporator        of the heat pump is thermally coupled to the heat sink return        for absorbing heat.

In some embodiments, the heat sink feed and the heat sink return form aheat sink circuit for a fluid, wherein the fluid of the heat sink returnis heated at least by the heat exchanger. After heating by the heatexchanger, the heat sink return becomes the heat sink feed. Thus, theheat sink feed has a higher temperature than the temperature of the heatsink return.

The heat source feed and the heat source return may form a heat sourcecircuit for a fluid, wherein the fluid of the heat source feed is cooledat least by means of the heat exchanger and its heat transmitted atleast partially to the heat sink return for forming the heat sink feed.After cooling of the heat source feed by the heat exchanger, the heatsource feed becomes the heat source return. The heat source return mayalternatively or additionally be diverted partially or completely andthus not be returned partially or completely to the heat source.

Relative arrangements, for example the arrangement of one elementimmediately before or immediately after a further element of the device,refer to a direction of a circuit and/or a flow direction of a fluid,for example to a direction of a heat sink circuit. The heat sink circuitis formed by means of the heat sink feed and the heat sink return.

In some embodiments, the evaporator, which is thermally coupled to theheat sink return, allows a reduction in the temperature of the heat sinkreturn. Thus, the heat source is further cooled so the heat yield isincreased. For this, the evaporator may be not in direct contact withthe heat source. In this way, the evaporator may be fitted later toexisting systems without making apparatus changes to the heat source.

The heat extracted from the heat sink return by means of the evaporatoris transmitted to the heat sink feed by means of the condenser of theheat pump. In this way, the use of the heat content of the heat sourcecan be improved and hence more heat or a higher thermal output or ahigher temperature for the heat sink can be provided. In other words, byincluding the heat pump in the heat sink circuit as taught herein, theheat sink return is cooled further and the heat sink feed heatedfurther.

With an industrial waste heat source (heat source), the heat sourcereturn according to the prior art must be cooled by means of coolingdevices, in particular cooling towers, before it can be discharged forexample as a wastewater stream. With the further cooling of the heatsink return taught herein, accordingly the heat source return is cooledmore greatly so that complex and cost-intensive cooling devices forcooling the heat source return may be omitted. In addition, thetemperature of the heat sink feed may be increased by means of thecondenser of the heat pump. In this way, the use of the heat content ofthe waste heat source is improved.

With a geothermal source (geothermal heat source), the heat sourcereturn is cooled more greatly so that its heat yield is improved.Furthermore, there is a prospecting risk for geothermal sources. Thisrisk arises from the fact that the temperature and potential mass flowof the thermal water from the borehole cannot be predicted withsufficient reliability. The teachings of the present disclosure maytherefore significantly reduce said risk or avoid the conclusion ofcostly insurance policies.

In some embodiments, a method for increasing the heat yield of a heatsource with a device as taught herein or one of its embodimentscomprises at least the following steps:

-   -   heat transmission from the heat source to the heat sink return        by means of the heat exchanger;    -   heat transmission from the condenser of the heat pump to the        heat sink feed;        characterized by a heat transmission from the heat sink return        to the evaporator of the heat pump.

The methods described provide similar and equivalent advantages to thoseof the devices.

In some embodiments, the device comprises the heat source, wherein afterthe evaporator, in particular directly after the evaporator of the heatpump, the heat sink return is thermally coupled to the heat source bymeans of the heat exchanger for absorbing heat. Thereby the heat of theheat source and the heat obtained from cooling the heat sink return bymeans of the heat pump are provided for the heat sink, in particular fora heat consumer.

In some embodiments, the condenser of the heat pump is thermally coupledto the heat sink return by means of a bypass line. An increased thermaloutput may thereby be provided for the heat sink.

In some embodiments, the heat sink is part of a district heatingnetwork. The thermal output of the district heating network may therebybe increased.

In some embodiments, the heat source is a geothermal source (geothermalheat source) and/or an industrial waste heat source. The temperature ofthe heat source return of the geothermal source may thereby be furtherreduced, so that the geothermal source may be cooled better and henceits yield improved. For the industrial waste heat source, advantageouslycomplex and cost-intensive cooling devices for cooling the heat sourcereturn may thereby be omitted.

In some embodiments, the heat pump is configured as a high-temperatureheat pump. A high-temperature heat pump is a heat pump which allows aheat provision at its condenser above 90 degrees Celsius, in particularabove 100 degrees Celsius. Thereby the temperature of the heat sink feedmay be further raised. In particular, the temperature of the heat sinkfeed may be raised to above 90 degrees Celsius. In other words,advantageously the temperature of the heat source may be furtherutilized.

To achieve said high temperatures, the heat pump may use a working fluidwith R1233zd, R1336mzz, butane, cyclopentane and/or with a fluoroketoneand/or a mixture of said substances.

In some embodiments, the heat pump has an electrical power of at least 1Megawatt. Thereby a heat pump is provided which is adequatelydimensioned for industrial applications. In particular, said electricalpower may be advantageous for a district heating network or a return ofprovided heat into an industrial process.

FIG. 1 shows the yield of a heat source 6 formed as a geothermal heatsource, by means of a heat pump 4 according to the prior art. The yieldof the geothermal source 6 is achieved by means of a known device 10comprising a heat sink 2. The heat pump 4 comprises at least onecondenser 41 and an evaporator 42. In connection with the evaporator 42,the geothermal source 6 has a heat source feed 61 and a heat sourcereturn 62. Here, the temperature of the heat source return 62 is lowerthan the temperature of the heat source feed 61 because of the thermalcoupling with the evaporator 62 of the heat pump 4. In other words, heatis transmitted from the geothermal source 6 to the evaporator 42 of theheat pump 4. The heat is transmitted to the heat pump 4 by the at leastpartial evaporation of the working fluid inside the evaporator 42.

In connection with the thermal coupling with the condenser 41 of theheat pump 4, the heat sink 2 has a heat sink feed 21 and a heat sinkreturn 22. The temperature of the heat sink return 22 is lower than thetemperature of the heat sink feed 21, or the temperature of the heatsink feed 21 is higher than the temperature of the heat sink return 22.In other words, the temperature of the heat source feed 61 is raised bymeans of the heat pump 4, and heat is emitted to the heat sink 2 bycondensation of the working fluid inside the condenser 41 via the heatsink feed 21.

One disadvantage of the known device 10 is that the temperature of theheat source return 62 cannot be reduced or lowered further. In otherwords, the yield of the geothermal source 6 is restricted by the heattransmission from the geothermal source 6 to the heat pump 4.

FIG. 2 shows the device 1 according to the first embodiment of theteachings herein. The device 1 comprises a heat pump 2 with a condenser41 and an evaporator 42. Furthermore, the device 1 comprises a heatsource 6 and a heat sink 2, in particular a heat consumer whichparticularly preferably is part of a district heating network, and aheat exchanger 12.

The heat pump 4 may comprise a compressor and an expansion valve. Aworking fluid of the heat pump 4 is at least partially condensed bymeans of the condenser 41, at least partially compressed by means of thecompressor, at least partially evaporated by means of the evaporator 42,and at least partially expanded by means of the expansion valve. Theworking fluid may be R1233zd, R1336mzz, butane, cyclopentane and/or afluoroketone and/or a mixture of said substances.

In connection with the heat exchanger 12, the heat source 6 has a heatsource feed 61 and a heat source return 62. In the exemplary embodimentdepicted, the temperature of the heat source feed 61 is for example 95degrees Celsius. The temperature of the heat source return 62 is forexample 35 degrees Celsius.

Furthermore, in connection with the heat exchanger 12 which couples theheat source 6 thermally to the heat sink 2, the heat sink 2 has a heatsink feed 21 and a heat sink return 22. The condenser 41 of the heatpump 4 is thermally coupled to the heat sink feed 21. In other words,the working fluid of the heat pump 4 is at least partially condensed bysaid thermal coupling and the heat thus released is transmitted to theheat sink feed 21. Here, said thermal coupling takes place directlyafter the heat exchanger 12. The evaporator 42 of the heat pump 4 isthermally coupled to the heat sink return 22. In other words, heat isextracted from the heat sink return 22 by means of the evaporator 42 andtransmitted to the heat sink feed 21 by means of the heat pump 4 and thecondenser 41. This allows further cooling of the heat sink return 22, sothat via the thermal coupling by means of the heat exchanger 12, theyield of the heat source 6 can be further improved.

For example, the temperature of the heat source feed 61 may be around 95degrees Celsius [° C.]. Directly after the thermal coupling of the heatsource 6 to the heat sink 2 by means of the heat exchanger 12, the heatsource return 62 has a temperature of approximately 35 degrees Celsius.Between the heat exchanger 12 and the condenser 41 of the heat pump 4,i.e. directly after the heat exchanger 12 and directly before thecondenser 41 of the heat pump 4, the heat sink feed 21 has a temperatureof around 90 degrees Celsius. Because of the absorption of heat by meansof the heat pump 4, the heat sink feed 21 has a temperature of more thandegrees Celsius directly after the thermal coupling to the condenser 41of the heat pump 4.

The heat sink 2 may comprise a heat consumer and consume or use at leastpart of the heat which can be supplied to it by means of the heat sinkfeed 21. Thus, the heat sink return 22 has a lower temperature ofapproximately 50 degrees Celsius. A temperature of around 50 degreesCelsius then prevails at the evaporator 42 of the heat pump 4. Furtherheat is extracted from the heat sink return 22 by means of theevaporator 42 of the heat pump 4, so that the temperature of the heatsink return 22 is approximately 30 degrees Celsius after the thermalcoupling to the evaporator 42 of the heat pump 4. The heat sink return22 with a temperature of around 30 degrees Celsius is then conducted tothe heat exchanger 12. There the heat sink return 22 again absorbs heatfrom the heat source 6 and reaches the heat sink feed 21 at atemperature of approximately 90 degrees Celsius. By means of the devices1 taught herein, the heat content of the yield of the heat source 6 maybe improved. As shown, the heat source 6 may comprise a geothermalsource.

FIG. 3 shows the device 1 according to a second embodiment of theteachings of the present disclosure. The device 1 from FIG. 3 heresubstantially comprises the same elements as the device in FIG. 2, sothat the statements made in relation to FIG. 2 may be transferreddirectly to the device 1 depicted in FIG. 3. In addition to theexemplary temperatures named in FIG. 2, exemplary mass flows [kg/s] areshown in FIG. 3, together with the electrical power supplied and thermaloutput extracted [MW] as examples.

The heat pump 4 receives for example an electrical power ofapproximately 2 Megawatt. The heat source 6, which in FIG. 3 is formedas a geothermal source, has a thermal output of approximately 15Megawatt. By increasing the heat from the heat source 6 by means of theheat pump 4 and its integration in the heat sink return 22 and heat sinkfeed 21, a thermal output of around 17 Megawatt can be provided for theheat sink 2.

In contrast to FIG. 2, the condenser 41 of the heat pump 4 isadditionally thermally coupled to the heat sink return 22 by means of abypass line 23. For this, the bypass line 23 has a pump 8 which pumps atleast part of a fluid from the heat sink return 22 to the condenser 41of the heat pump 4. The thermal coupling of the condenser 41 of the heatpump 4 to the heat sink return 22 depicted allows an increase in thethermal output provided for the heat sink 2. In the embodiment shown inFIG. 3, accordingly essentially the thermal output for the heat sink 2may be increased. In the embodiment shown in FIG. 2 however, essentiallythe temperature for the heat sink 2 is increased.

The further elements of the device 1 are arranged and/or integrated in acomparable or identical fashion to the elements of FIG. 2, so thestatements made with reference to FIG. 2 may be transferred to thedevice 1 shown in FIG. 3. Although the teachings herein have beenillustrated and described in detail in the form of exemplaryembodiments, the scope of the teachings is not restricted by theexamples disclosed, and other variations may be derived therefrom by theperson skilled in the art without leaving the scope of protection of thedisclosure.

What is claimed is:
 1. A device for increasing the heat yield of a heatsource, the device comprising: a heat sink; a heat pump with a condenserand an evaporator; and a heat sink feed and a heat sink return providinga thermal coupling to the heat source by a heat exchanger; wherein thecondenser is thermally coupled to the heat sink feed for emitting heatto the heat sink; and the evaporator is thermally coupled to the heatsink return for absorbing heat.
 2. The device as claimed in claim 1,further comprising the heat source; wherein downstream of the evaporatorof the heat pump, the heat sink return is thermally coupled to the heatsource by the heat exchanger for absorbing heat.
 3. The device asclaimed in claim 1, wherein the condenser of the heat pump is thermallycoupled to the heat sink return by a bypass line.
 4. The device asclaimed in claim 1, wherein the heat sink is part of a district heatingnetwork.
 5. The device as claimed in claim 1, wherein the heat sourcecomprises a geothermal source and/or an industrial waste heat source. 6.The device as claimed in claim 1, wherein the heat pump comprises ahigh-temperature heat pump.
 7. The device as claimed in claim 6, whereinthe heat pump uses a working fluid comprising at least one of: R1233zd,R1336mzz, butane, cyclopentane, a fluoroketone, and a mixture of saidsubstances.
 8. The device as claimed in claim 1, wherein the heat pumphas an electrical power of at least one Megawatt.
 9. A method forincreasing the heat yield of a heat source, the method comprising:transmitting heat from the heat source to a heat sink return using aheat exchanger; transmitting heat from a condenser of a heat pump to aheat sink feed; and transmitting heat from the heat sink return to anevaporator of a heat pump; wherein the heat sink feed and the heat sinkreturn provide a thermal coupling to the heat source by the heatexchanger; wherein the condenser is thermally coupled to the heat sinkfeed for emitting heat to the heat sink; and wherein the evaporator isthermally coupled to the heat sink return for absorbing heat.